Seattle author Michael Gruber’s publishers are marketing his riveting new book as a thriller: The jacket of “The Return” shows a stylized skull, Mexican Day of the Dead style, its features an arrangement of guns, grenades and ammo.

No question, the book’s a thriller — a terrifically entertaining one. (Ordnance-heavy too, which justifies that jacket.)

But “The Return” is much more.

That’s because Gruber has never shied from Big Questions. Life, death, love, sex, faith, greed, violence, compassion — he’s taken pensive (and often quite funny) looks at such stuff for years, through novels such as “The Book of Air and Shadows” and “The Good Son.”

Adding to this combo plate of action and amused reflection is Gruber’s flair for vigorous prose and character development. He likes and cares about the people in his books — and shows us why we should, too.

Take Richard Marder. Marder seems like an ordinary guy: a cultured, wry, late middle-aged Manhattan book editor. But there’s some interesting stuff under the surface.

Like millions of dollars, ethically earned but a secret from even those closest to him. His fortune gives Marder the freedom to do pretty much what he wants. A harrowing history in Vietnam has given him a strong stomach for violence. And he has a powerful need for vengeance.

So when his doctor explains an X-ray to him — it’s a death sentence, which could come due anytime — Marder’s first thought is: Mexico. It’s the homeland of his beloved late wife, Chole — and to the drug lords who murdered his in-laws, triggering Chole’s madness and death.

Motive, means and the knowledge that he’s got nothing to lose. It’s a combination strong enough to send Marder on a relentless quest.

Once settled, they turn the villa into the hub of an ambitious economic enterprise for the region, with significant hands-on aid from Marder’s engineer daughter Carmel. (Worried that Dad’s gone nuts, she’s tracked him down and invited herself.)

Their efforts deliberately antagonize the drug lords. Simultaneously, the pair talk to some guys Skelly knows about weapons, organize a ragtag army, and transform the villa into a badass fortress. War is inevitable.

But this book isn’t just bang-bang, shoot-shoot. For one thing, a few twists keep the plot from becoming predictable. And flashbacks illuminate the love/hate bonds that Skelly and Marder forged in Vietnam. The flashbacks trigger other rich layers of the story too, notably the tension between Marder’s profound religious faith and Skelly’s and Carmel’s deep skepticism about it.

So “The Return” works brilliantly on two levels. It’s a provocative, bittersweet look at the Big Questions. But it’s also a deeply satisfying thriller — sometimes violent, often dryly funny, and always intriguing.

Adam Woog’s column on crime and mystery fiction appears on the second Sunday of the month in The Seattle Times.